It sounds like your microphone cable might be picking up interference from an electronic device. I would suggest that you try and reroute the microphone cable away from any electronic devices and try again.
Is the call quality only bad while driving or also when the engine is idling when parked? Try to hear if there is a sound quality difference with the engine switched off and idling?
Also ensure that the ground connections of your radio are secure and that the wiring to the ground connections is sound
How to test wiring:
Please let us know how you get along.
Thursday, April 29th, 2021 AT 6:16 AM